Many products, including consumer, health care, and professional products, are more effectively used by an end user when the product includes a feature that can communicate or signal to the user a particular condition or indicate the relative level or degree of use. One example is a visual indicator that causes the product to display a color. Color indicators can either indicate a change in a condition or a degree of use through a change from colorless to a color, or through an increase in color intensity.
Exemplary conditions that can be monitored with a color indicator include the presence of moisture. Exemplary consumer products that can be more effective and deliver more benefits to end users by incorporating a suitable color indicator include absorbent articles having synthetic polymeric substrates incorporated therein, such a diapers, training pants, incontinence products and the like. Such substrates are often used as liquid barriers.
Color indicators are well known and are available in various forms. Many known color indicators can be applied to substrates in liquid form at room temperature by various printing methods such as stamping, ink jet, flexographic and gravure printing methods. However, the presently available color-developing types of color indicators remain tacky after they are applied to synthetic polymeric substrates. Such color indicators are therefore not suitable for use in absorbent articles because at the very least, the tackiness causes manufacturing problems.
While the color-changing compositions known in the art provide certain benefits, there remains a need for a color-developing type of color indicator that can be applied to certain polymeric substrates and that exhibit low tack. There also remains a need for a composition that is durable, is non-leachable and that shows a readily-discernible color change when the composition is used in a product. Further, there remains a need for a composition having the above characteristics that can be applied to substrates using a printing technique.